设计模式——结构型

1.装饰器模式

要素：装饰器，装饰对象
为待装饰对象中某一结构特征添加内容，而不是新建一个特征

/**
 * 装饰对象
 */
public interface Shape {
   
    public void draw();
}
/**
 * 具体装饰对象
 */
public class Circle implements Shape{
   
    private String TAG = "Circle";
    @Override
    public void draw() {
   
        Log.d(TAG,"draw circle");
    }
}

/**
 * 装饰器
 */
public abstract class ShapeDecorator implements Shape{
   
    protected Shape shape;
    private String TAG = "ShapeDecorator";

    public ShapeDecorator(Shape shape) {
   
        this.shape = shape;
    }
}
/**
 * 具体装饰器，当只有一个待装饰对象时可不需要抽象装饰器
 */
public class ColorDecorator extends ShapeDecorator {
   
    private String TAG = "ColorDecorator";
    public ColorDecorator(Shape shape) {
   
        super(shape);
    }

    //原结构方法
    public void draw() {
   
        shape.draw();
        setColor();
    }

    //给原结构添加的装饰
    private void setColor() {
   
        Log.d(TAG,"set color");
    }
}

//测试
Circle circle = new Circle();
ColorDecorator colorCircle = new ColorDecorator(circle);
colorDecorator.draw();

输出log：